Thermal spray powders for wear-resistant coatings, and related methods

Abstract

A method of making a thermal spray powder is provided. The method comprises: providing a powder comprising a plurality of porous particles; infiltrating a mixture comprising a solvent and a plurality of solid lubricant particles into the porous particles; and heating the powder to a temperature sufficient to evaporate the solvent. The method of forming a wear-resistant coating is provided. The method comprises: providing a thermal spray powder; heating the thermal spray powder; and accelerating the thermal spray powder from a thermal spray gun onto the substrate, to form a deposit. Yet another embodiment provides a wear resistant coating. The wear resistant coating is formed by thermally spraying the thermal spray powder.

1 . A method of making a thermal spray powder, the method comprising:
 providing a powder comprising a plurality of porous particles;   infiltrating a mixture comprising a solvent and a plurality of solid lubricant particles into the porous particles, and   heat-treating the powder to a temperature sufficient to evaporate the solvent.   
     
     
         2 . The method of  claim 1 , wherein the porous particles comprise a material selected from the group consisting of a metal, a metal alloy, a ceramic, a cermet, and combinations thereof. 
     
     
         3 . The method of  claim 2 , wherein the metal comprises at least one metal selected from the group consisting of titanium, nickel, iron, cobalt, chromium, aluminum, and yttrium. 
     
     
         4 . The method of  claim 2 , wherein the ceramic comprises a material selected from the group consisting of aluminum oxide, chromium oxide, chromium-carbide, tantalum carbide, titanium diboride, titanium oxide, tungsten-carbide, and titanium carbide. 
     
     
         5 . The method of  claim 2 , wherein the cermet comprises a material selected from the group consisting of tungsten carbide-cobalt, nickel aluminide, nickel chrome-chrome carbide, and tungsten carbide-cobalt chrome. 
     
     
         6 . The method of  claim 5 , wherein the cermet comprises a material selected from the group consisting of tungsten carbide-cobalt and tungsten carbide-cobalt chrome. 
     
     
         7 . The method of  claim 1 , wherein the porous particles have an average pore size in the range from about 1 micrometer to about 10 micrometers. 
     
     
         8 . The method of  claim 7 , wherein the porous particles have an average pore size in the range from about 1 micrometer to about 5 micrometers. 
     
     
         9 . The method of  claim 1 , wherein the porous particles have a porosity in a range of from about 1% to about 90%. 
     
     
         10 . The method of  claim 1 , wherein the solid lubricant particles comprise at least one material selected from the group consisting of a fluoride, a nitride, a sulfide, carbon, and boric acid. 
     
     
         11 . The method of  claim 10 , wherein the solid lubricant particles comprise at least one material selected from the group consisting of hexagonal boron nitride, graphite, molybdenum disulfide, tungsten sulfide, calcium difluoride, calcium-barium difluoride, polytetrafluoroethylene, carbon, and boric acid. 
     
     
         12 . The method of  claim 10 , wherein the solid lubricant particles comprise hexagonal boron nitride. 
     
     
         13 . The method of  claim 1 , wherein the solid lubricant particles have an average particle size less than about 5 micrometers. 
     
     
         14 . The method of  claim 13 , wherein the solid lubricant particles have an average particle size in the range from about 20 nanometers to about 3 micrometers. 
     
     
         15 . The method of  claim 1 , wherein the solvent comprises a material selected from the group consisting of water, acetone, and alcohol. 
     
     
         16 . The method of  claim 15 , wherein the solvent comprises water. 
     
     
         17 . The method of  claim 1 , wherein infiltration comprises at least one process selected from the group consisting of injection, vacuum infiltration, and capillary filling of the solution. 
     
     
         18 . The method of  claim 17 , wherein infiltration comprises vacuum-infiltration. 
     
     
         19 . The method of  claim 18 , wherein the vacuum infiltration comprises contacting the porous particle with the solution at a pressure of at least about −1.0 bar. 
     
     
         20 . The method of  claim 1 , wherein heat-treating comprises heating to a temperature in a range from about 20° C. to about 250° C. 
     
     
         21 . The method of  claim 1 , wherein the thermal spray powder comprises the solid lubricant particles in an amount of at least about 5 volume percent. 
     
     
         22 . The method of  claim 1 , wherein the thermal spray powder comprises the solid lubricant in an amount in a range of about 5 volume percent to about 80 volume percent. 
     
     
         23 . A method of making a thermal spray powder, the method comprising:
 providing a powder which comprises porous particles of cobalt tungsten carbide;   vacuum-infiltrating a mixture comprising water and hexagonal boron nitride into the porous particles, and   heat-treating the powder to a temperature sufficient to evaporate the solvent.   
     
     
         24 . A method of forming a wear-resistant coating on a substrate, the method comprising:
 providing a thermal spray powder;   heating the thermal spray powder; and   accelerating the thermal spray powder from a thermal spray gun onto the substrate, to form a deposit, wherein the thermal spray powder is formed by the process of:   providing a powder comprising a plurality of porous particles;   infiltrating a mixture comprising a solvent and a plurality of solid lubricant particles into the porous particles, and   heat-treating the powder to a temperature sufficient to evaporate the solvent.   
     
     
         25 . The method of  claim 24 , wherein the porous particles comprise a material selected from the group consisting of a metal, a metal alloy, a ceramic, a cermet, and combinations thereof. 
     
     
         26 . The method of  claim 24 , wherein the solid lubricant particles comprise at least one material selected from the group consisting of hexagonal boron nitride, graphite, molybdenum disulfide, tungsten sulfide, calcium difluoride, calcium-barium difluoride, polytetrafluoroethylene, carbon, and boric acid. 
     
     
         27 . A wear-resistant coating formed by the method of  claim 24 . 
     
     
         28 . A turbomachine containing at least one surface covered by the wear-resistant coating of  claim 27 .